Rifle bolt mechanism and safety

ABSTRACT

A breech bolt firearm in which the bolt is mounted turnably but axially immovable in a guide sleeve is improved by placing a projection on part of the bolt which when aligned with a longitudinal recess provided on the sleeve allows dismantling of the breech bolt mechanism. Also a safety is provided which latches both the firing pin nut and the bolt handle.

The present invention relates to a rifle bolt mechanism of the turningbolt action type where the bolt is movable relative a breech mechanismand by turning is lockable in the firing position in the breechmechanism, and where a firing pin united with a firing pin nut isarranged in the bolt, which is provided with a handle for operation, thefiring pin nut being mounted non-rotatably but axially displaceably in aguide sleeve, which in turn is displaceably mounted in the breechmechanism.

A well-known example of this type of rifle bolt mechanism is the Mausermechanism. One of the disadvantages with this type of mechanism is thatthe guide for the bolt is very short, which causes the axial movementsof the bolt in the breech mechanism to be jerky as a result of the boltcoming out of alignment. This makes handling the weapon more difficult,inter alia for marksmanship shooting.

To obtain a better guidance of the bolt, it has been proposed in theSwedish published specification No. 339 645 to mount a guiding forkrearward of the breech mechanism for guiding the bolt. However, such amounting fork makes the weapon more complicated and also requires extraspace. Furthermore, precision will not be as good as when the improvedguide is incorporated in the mechanism to start with.

The object of the invention is to provide an improved rifle boltmechanism where the bolt is very well guided in the breech mechanism. Afurther object of the invention is to provide a bolt mechanism which issimple and reliable from the aspects of manufacture and maintenance.

These objects are achieved in accordance with the invention by the voltbeing mounted turnably but axially immovably in the guide sleeve andbeing guided in the breech mechanism via the guide sleeve. The bolt issuitably guided here in the guide sleeve along the major portion of itslength, and a particularly advantageous embodiment is obtained if theforward end of the guide sleeve, when the bolt is in the firingposition, reaches substantially as far as the forward end of the breechmechanism cartridge opening.

By both the firing pin nut and bolt being accommodated in the guidesleeve, it can be made very long. This results in that the bolt is givenvery good axial guidance, thus obtaining a smooth and comfortableaction, without any binding tendency. Furthermore, the bolt is givenvery good mounting for rotation, with the consequence that its forwardend may be given an exact locking position reltive the cartridgeposition, which is essential for precision weapons.

Further distinguishing features and advantages of the invention will beperceived from the following description and claims.

The invention will now be described in detail with the aid of anembodiment illustrated on the accompanying drawing, where:

FIG. 1 is a side view of a breech mechanism where a bolt mechanism inaccordance with the invention is shown in the firing position;

FIG. 2 is a view from above of the breech mechanism in FIG. 1, with thebolt mechanism in a partially withdrawn position;

FIG. 3 is a side view of the bolt mechanism in accordance with theinvention in the state it is in after being spring-biassed;

FIG. 4 is a view from below of the bolt mechanism of FIG. 3 afterfiring;

FIG. 5 is the same view as in FIG. 4 but with the bolt mechanism readyfor dismantling;

FIG. 6 illustrates the bolt mechanism in FIG. 5 in a dismantled state;

FIG. 7 is a perspective view of the guide sleeve;

FIG. 8 is a perspective view of the firing pin with its associated nut;

FIG. 9 is a perspective view of a detail of the bolt;

FIG. 10 is a section along the line X--X in FIG. 6; and

FIG. 11 illustrates the function of a safety device.

In an inventive rifle bolt mechanism, as is apparent from FIGS. 1 and 2,a breech mechanism 1 is displaceably mounted in a breech mechanism 2,the forward end of which is attached to a barrel 3. The breech mechanism2 is intended to be provided on its underside with a triggeringarrangement 4, which may be of conventional type, and therefore does notneed to be described in detail in this connection.

In FIG. 1 the bolt mechanism is illustrated in its forward position withthe bolt handle 5 pushed down in a transverse slot 6 in the breechmechanism 2. A guide sleeve 7 enclosed in the bolt mechanism 1 thenreaches with its forward end up to the same position as the forward endof the cartridge opening 8 of the breech mechanism. The cartridgeopening 8 is backwardly defined by an upper cross piece 9 on the breechmechanism 2.

In the situation illustrated in FIG. 2, the bolt handle 5 has beenturned upwards out of the slot 6, the bolt mechanism 1 then having beenmoved backwards some way with the aid of the handle 5. During turningand the axial movement of the bolt 10 with the aid of its handle 5,locking abutments 11 forwards on the bolt 10 have been moved incomplementary locking grooves 12 situated forwards in the breechmechanism 2 so that the bolt 10 is no longer locked in the firingposition. The bolt 10 is mounted in the guide sleeve 7 and is guidedduring its axial movement by the breech mechanism 2 via the guide sleeve7. A firing pin nut 13, also included in the bolt mechanism 1 is mountedin the guide sleeve 7 as well as the bolt 10. When the handle 5 isturned upwards from the position illustrated inFIG. 1 to thatillustrated in the position 2, the bolt mechanism 1 will bespring-biassed, the nut 13 being moved backwards in the guide sleeve 7,as will be described in detail later. The guide sleeve 7 is providedalong its sides with longitudinal guide ridges 14 and 15, moving incomplemental grooves in the breech mechanism 2.

By moving the bolt mechanism 1 fully backwards from the positionillustrated in FIG. 2, and after releasing required latches, the boltmechanism 1 can be completely removed from the breech mechanism 2. Abolt mechanism 1, just removed from the breech mechanism 2, isillustrated inFIG. 3. As will be seen, the bolt 10 is guided in theguide sleeve 7 for the major part of its length. On the rearward part ofthe bolt 10 there is a cam profile 16 co-acting with a biassing tooth 17on the firing pin nut 13. The cam profile 16 is formed such that onturning the bolt handle 5 from the position illustrated in FIG. 1 tothat in FIG. 2, it urges the biassing tooth 17, and thereby also the nut13, rearwards so that the bolt mechanism is spring-biassed and thefiring pin nut 13 assumes the firing position. When the mechanism 1 isthen moved forwards in the breech mechanism, a support surface 18 on thefiring pin nut 13 will be brought into engagement with the triggeringarrangement 4 and prevent the forward movement of the nut 13. The handle5 can then be turned down into the position illustrated in FIG. 1without the nut 13 moving forwards.

On firing, latching from the triggering arrangement 4 against thesupport surface 18 ceases, and the parts in the bolt mechanism 1 assumethe relative positions illustrated in FIG. 4, where the firing pin 13 isin a position moved forwards relative the guide sleeve 7. The boltmechanism 1 is seen from below in FIG. 4.

By moving the firing pin nut 13 backwards a sufficient length, from theposition illustrated inFIG. 4 and against bias from the firing pinspring, the bolt 10 may be turned to the position illustrated in FIG. 5,in which the bolt mechanism 1 may be dismantled. The bolt 10 comprises afirst part 19 and a second part 20, which are non-rotatably attached toeach other in an assembled condition. The first part 19 is elongate andhas a circular cross-section. At its forward end it carries the lockingabutments 11 and at its rearward end it is provided with a radialprojection 21 for engagement in a recess 22 (see FIG. 6) in the forwardend of a sleeve 23 included in the second part 20, the first part 19being inserted in the sleeve 23. The bolt mechanism 1 can now be takenapart by pulling the first part 19 forwards out of the guide sleeve 7.The remaining second part 20 together with the firing pin nut 13 maythen be lifted out of the guide sleeve.

The bolt mechanism 1 is illustrated in an entirely dismantled state inFIG. 6, where the different parts are illustrated with the sameorientation as in FIG. 5. As will be seen from FIG. 6A, the guide sleeve7 is provided with a circumferential locking groove 24, the width ofwhich corresponds to the length of the sleeve 23. As will have beenunderstood already, this locking groove 24 has an opening on theunderside of the guide sleeve which is sufficiently large for the sleeve23 to be inserted into the locking groove 24 from the underside of theguide sleeve 7. There is a recess 25 in one wall of the guide sleeve 7for enabling the necessary rotation of the second part 20. The lockinggroove 24 is forwardly defined by a support surface 26, the radialextension of which substantially corresponds to the material thicknessof the sleeve 23 and the radial extension of the radial projection 21 onthe first part 19. The first part 19 is locked axially forwards inrelation to the guide sleeve 7 when the radial projection 21 is incontact with the support surface 26. A second radial support surface 27restricts the locking groove 24 rearwards and is intended to co-act withthe rear end of the sleeve 23 for locking the first part 19 axiallybackwards via the radial projection 21. The guide sleeve 7 has a bore 28intended for the first part 19. In connection with the bore 28 there isa first longitudinal recess 29 for the radial projection 21 of the firstpart 19. In this case the first recess 29 comprises a slot arranged onthe underside of the guide sleeve 7, the width of the slot being lessthan the diameter of the bolt first part 19. Behind the locking groove24 there is a second recess 30 in the guide sleeve 7 for the firing pinnut 13, the recess having the form of a longitudinal open slot towardsthe underside of the guide sleeve. In this slot there is a supportsurface 31 facing towards the forward end of the guide sleeve.

As will be seen from FIG. 6B, the first part 19 of the bolt is providedwith an elongate hole 32 for the firing pin 33 and associated spring 34,illustrated in FIG. 6C. The firing pin 33 is rigidly connected to thefiring pin nut 13 and carries a displaceably mounted support member 35biassed by the firing pin spring 34, the member 35 thus being movablerelative the nut 13. In an assembled state, this support member 35 isintended to be in contact with the support surface 31 in the guidesleeve 7.

Further details in the embodiment of the guide sleeve 7 will be seenfrom FIG. 7. The implementation of the firing pin nut 13 and the supportmember 35 relatively movable thereto will be seen from FIG. 8. Acylindrical portion 36 on the support member 35 is intended to fit intothe hole 32 in the bolt first part 19.

As will be seen in better detail from FIG. 9, the radial projection 21on the first part 19, together with the sleeve 23 in the second part ofthe bolt, forms a radial locking means 37 intended for accommodation inthe locking groove 24 in the guide sleeve 7. The turning lock betweenthe sleeve 23 and the first part 19 can of course be formed in aplurality of other ways than what has been illustrated here.

As will be seen from FIG. 10, the guide ridges 14 and 15 on the guidesleeve 7 are accommodated in corresponding grooves in the breechmechanism 2. Good guidance may be obtained merely with the aid of theguide ridges and the grooves, but it is also possible further to improvethe guidance by allowing the walls of the guide sleeve to co-act withthe walls of the breech mechanism. Furthermore,the locking abutments 11'and 11" on the bolt can to advantage have a shape and location such thatthey run in the same grooves as the guide ridges 14 and 15 when the bolt10 is moved axially in the breech mechanism.

The rifle mechanism illustrated here should naturally be supplemented bysuch details as shell extractor and shell ejector. For the sake ofclarity these details have been left out, but their embodiment shouldnot cause one skilled in the art any problems, since a large number ofusable solutions exist.

The sleeve 23 included in the second part 20 of the bolt 10 can beprecision-cast to advantage, machining of the cam profile 16 thus beingeliminated. Since the first part 19 of the bolt also has a simple shape,manufacture of the bolt itself is considerably simplified, thisotherwise being often complicated and expensive. By the simple lockingdetermined by its form between the guide sleeve 7 and the part mountedin it, there are avoided complicated arrangements for mutual lockingbetween the parts. In the embodiment illustrated here, the first recess29 comprises a slot in the guide sleeve, but it is also quite possibleto have a depression in connection with the bore 28 instead of a slot,and thus have a guide sleeve closed on the underside, at least at thefirst part 19 on the bolt 10.

By its mounting in the guide sleeve 7, the bolt 10 obtains very goodguidance in the breech mechanism 2, both for axial and rotationalmovement. In turn this means that the bolt always has a well-definedfiring position in the breech mechanism, which is important for shootingaccuracy. This good guidance also enables smooth and comfortablehandling of the bolt mechanism.

To assemble the bolt mechanism, the bolt second part 20 is first thrustover the firing pin 33 with the recess 22 facing toward the tip of thepin. The firing pin nut 13 is then placed in the second recess 30 in theguide sleeve 7, while the bolt second part 20 is placed in the lockinggroove 24, with the recess 22 oriented in extension to the first recess29. The bolt first part 19 is then thrust into the bore 28 with theradial projection 21 accommodated in the first recess 29. After theradial projection 21 has moved into the recess 22 in the sleeve 23 andthe different parts of the bolt mechanism assume the positions indicatedin FIG. 5, the bolt is twisted in the guide sleeve 7 such that thedifferent parts of the bolt mechanism assume the positions illustratedin FIG. 3. The bolt mechanism 1 can now be inserted in the breechmechanism 2.

As will be seen from FIG. 6B and FIG. 10, there is a longitudinal recess38 in the guide ridge 14 on the guide sleeve 7, this recess beingdefined by an abutment surface 39 at the forward end of the guidesleeve. The recess 38 is intended for abutment means (unillustrated)arranged in the breech mechanism 2 such as to arrest, in co-action withthe abutment surface 39, the backward movement of the guide sleeve whenthe bolt mechanism has attained a fully withdrawn position.

The bolt mechanism can be provided with different types of safetydevices. For example, it is possible to mount a safety bolt intended forco-action with the firing pin nut 13 in the guide sleeve 7. Specialadvantages can, however, be achieved with a safety device 40 (FIG. 1)illustrated on the drawing, where a safety bolt 41 is rotatably mountedin the breech mechanism 2 for co-action with a recess 42 (FIG. 11)arranged in the firing pin nut 13. In the safety position, FIG. 11A, thesafety bolt 41 is in engagement with the recess 42, thus latchingagainst movement of the firing pin nut. At the same time, according toFig 1, a locking poriton 43 in the form of a tip on the operatingportion of the safety bolt 41 is in engagement with a stop means 44,suitably a groove, on the handle 5 such that turning the handle upwardsis prevented when the bolt mechanism is on safety. After turning thesafety bolt 41 away from its safety position, FIG. 11B, firing andturning up of the handle 5 may take place.

I claim:
 1. A rifle bolt mechanism of the turning bolt action type,wherein a bolt, which is provided with a handle, along the major part ofits length is mounted rotatably but axially undisplaceably in a guidesleeve, which guide sleeve guides the bolt in a breech mechanism, andwherein a firing pin united with a firing pin nut cooperates with thebolt, which bolt at its forward end is provided with locking abutmentsfor fixing the bolt in the firing position in the breech mechanism, saidbolt comprising an elongate first part and a second part carrying saidhandle, said first and second parts being formed for non-rotatableconnection to each other, and there being provided in the guide sleevean annular locking groove for the bolt at the rear end of a bore forsaid first part of the bolt, characterized in that in the guide sleevethere extends between its forward end and the locking groove a firstlongitudinal recess for a radial projection at the rear of said firstpart of the bolt, said radial projection being adapted to engage thelocking groove, which in the underside of the guide sleeve has anopening via which a second sleeve included in said second part of thebolt can be radially inserted into said locking groove, whereby thefirst part of the bolt, after axial insertion into the guide sleeve andinto the second sleeve inserted into the guide sleeve, may be turnedtogether with the second part of the bolt in the guide sleeve torotatably hold the bolt in the guide sleeve.
 2. Rifle bolt mechanism asclaimed in claim 1, characterized in that the second part (20) isprovided with a biassing cam profile (16) for the firing pin nut (13).3. Rifle bolt mechanism as claimed in claim 1, characterized in that thefirst longitudinal recess (29) comprises a slot arranged on theunderside of the guide sleeve (7), the width of the slot being less thanthe diameter of the bolt first part (19).
 4. Rifle bolt mechanism asclaimed in claim 3,, characterized in that the width of the slot (29) isgreater than the diameter of the firing pin spring (34), whereby thefiring pin nut (13) with associated firing pin (33) and firing pinspring (34) can be taken in and out of the guide sleeve (7) radially,with the sleeve (23) in the bolt second part (20) pushed over the firingpin.
 5. Rifle bolt mechansim as claimed in 1, characterized in that theguide sleeve (7) has a second recess (30) intended for the firing pinnut (13) and arranged behind the locking groove (24), the recess (30)preferably having the form of a longitudinal open slot on the undersideof the guide sleeve.
 6. Rifle bolt mechanism as claimed in claim 5,characterized in that there is a support surface (31) in the secondrecess (30) facing towards the forward end of the guide sleeve for asupport member (35), displaceable relative the firing pin nut (13)mounted on the firing pin (33) and biassed by the firing pin spring(34).
 7. Rifle bolt mechanism as claimed in claim 1, characterized inthat the guide sleeve (7) is provided with longitudinal guide ridges(14,15) for co-action with complementary guide grooves in the breechmechanism (2), whereby a guide ridge (14) is extending on one side ofthe guide sleeve along the entire length of the guide sleeve, while onthe other side of the guide sleeve the corresponding guide ridge (15)has an interruption at the position (25) for the bolt handle (5). 8.Rifle bolt mechanism as claimed in claim 7, characterized in thatlocking abutments (11',11") on the bolt (10) are arranged to beaccommodated in the same grooves as the guide ridges (14,15).
 9. Riflebolt mechanism as claimed in claim 1, characterized in that the bolthandle (5) may be turned down into a recess (6) at the rear part of thebreech mechanism (2) flush with a rear, upper cross piece (9) thereon.10. Rifle bolt mechanism as in claim 1 including a safety meanscomprising a safety bolt which is mounted in the breech mechanism andwhich in its safety position is arranged to latch both the firing pinnut and the bolt handle.